To ARS :
I don't have "yellow pipe " actually .. I have decoupler's but not between this engine and fuel tanks ...
to Physics Student:
.. i'm not sure what you think ... I just build it .. Can you explain what you think ??
I mean Mun ( but it's equal to Moon, no ?? :-) ) ... you think that newer version's are better ?? ... I mean that is not by version but by player ...